I have solved the mystery of the seven hour meters and I understand why I have no tickets when I return to my car in the Metro parking lot at the People’s Republic of Takoma Park Metro Station.
From 8:30 a.m. to 3:30 p.m., the meters have to be fed. If you park and don’t feed quarters to the meter, you get a ticket. Between the hours of 3:30 p.m. and 7:30 p.m., the meters are free. After 7:30 p.m. until 2:30 a.m., the spaces are again metered. And from 2:30 a.m. to 8:30 a.m., they are again free.
I think that’s just about the most bizarre set of parking meters I’ve ever seen, but so be it. I wonder if other lots in the Metro system have similar set ups?
Either way, mystery solved. Case closed.